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38 RabbitCore RCM3600
Reads the voltage of an analog input channel by serial-clocking an 8-bit command to the ADS7870 A/D
converter by the Direct Mode method. This function assumes that Mode1 (most significant byte first) and
the A/D converter oscillator have been enabled. See
anaInConfig()
for the setup.
The conversion begins immediately after the last data bit has been transferred. An exception error will
occur if Direct Mode bit D7 is not set.
PARAMETERS
cmd
contains a gain code and a channel code as follows.
D7—1; D6–D4—Gain Code; D3–D0—Channel Code
Use the following calculation and the tables below to determine
cmd
:
cmd = 0x80 | (gain_code*16) + channel_code
len
, the output bit length, is always 12 for 11-bit conversions
unsigned int anaInDriver(unsigned int cmd,
unsigned int len);
Gain Code Multiplier
0 x1
1 x2
2 x4
3 x5
4 x8
5 x10
6 x16
7 x20
Channel Code
Differential Input
Lines
Channel Code
Single-Ended
Input Lines
*
* Negative input is ground.
4–20 mA
Lines
0 +AIN0 -AIN1 8 AIN0 AIN0*
1 +AIN2 -AIN3 9 AIN1 AIN1*
2 +AIN4 -AIN5 10 AIN2 AIN2*
3
†
† Not accessible on RCM3600 Prototyping Board
+AIN6 -AIN7 11 AIN3 AIN3
4 -AIN0 +AIN1 12 AIN4 AIN4
5 -AIN2 +AIN3 13 AIN5 AIN5
6 -AIN4 +AIN5 14 AIN6 AIN6
7* -AIN6 +AIN7 15 AIN7 AIN7*